Typically, data is inputted into a computer by means of a QWERTY keyboard. This becomes cumbersome when inputting certain non-textual data or instructing the computer to execute certain commands. Time and effort is wasted, especially if the user has to frequently input such information. In order to make the human/machine interface more efficient and user-friendly, present computers often utilize special function keys, a mouse, pull-down menus, etc.
Special function keys execute a predetermined set of instructions to the computer by depressing a single key or key combinations. The mouse is a small hand-held box-like device which is typically coupled to the computer system by a cable and placed adjacent to the keyboard. Moving the mouse across a flat surface causes a moveable cursor on the computer's display screen to mimic the mouse's movements. Thus, the mouse is one of many cursor positioning devices which may be used to control a computer. One or more switches are provided on the mouse to signal the computer by depressing the switch that a desired location of the cursor on the display has been selected. The combination of moving the mouse to point the cursor to an object on the display screen and pressing the switch while the cursor is pointing to the object to select the object is called "point and click." Pull-down menus are used in conjunction with the mouse to help input commands to the computer. Pull-down menus and a mouse with a switch are described in U.S. Pat. No. Re. 32,632. A further description of pull-down menus may be found in U.S. Pat. No. 4,931,783.
In order to make the human/machine interface even more efficient and user-friendly, computers are being designed to recognize and respond to the user's spoken words. Optimally, this allows the user hands-free communication with the computer by allowing the user to speak into a microphone connected to the computer. A standard keyboard and/or mouse are also used in conjunction with the speech recognizer. This is due to limitations of the speech recognizer to correctly interpret context of human speech. A keyboard and a mouse is also used to allow an alternative method for interfacing with the computer (e.g., backup or if users feel more comfortable using the traditional method).
However, even though the speech recognition function enhances the input of data and commands to the computer, it has certain disadvantages over pure manual interfaces. One disadvantage is that the user can encounter difficulties in carrying on extraneous conversations because the machine would be listening and would be possibly falsely triggered into executing commands. Furthermore, loud background noises could also falsely trigger the speech recognizer.
This problem may be solved by employing a special button on the mouse, or a special function key or a switch on the keyboard or a footpedal switch. However, each of these except the mouse button pose disadvantages: a keyboard already has numerous keys and adding yet another key or switch makes operation that much more complicated; similarly, a footpedal switch makes operation more complicated, involves adding another port to the computer, running another cable and also increases cost by having to add on a special device.
Another problem associated with using a speech recognizer is that the user might desire the computer to effect changes on only certain objects on the display screen and not on the remainder.
Yet another problem with speech recognition interfaces is that the recognizer might erroneously interpret the spoken message or command.